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Re: Compressed Library was Re: Compressed LDraw files
avatarJanuary 31, 2013 11:24AM
One reason that zips are larger than compressed tar files is that each file in the zip is individually compressed. For this reason, a zipped tar file will usually be smaller than a zip of the tar file's contents. A tar.gz or tar.bz2 is just full tar file that has been run through gzip or bzip2 compression, so cross-file compression works there.

I'm not sure how 7-zip behaves with respect to cross-file compression, but cross-file compression I would think in theory be possible without requiring all the intervening files to be decompressed in order to get to a specific file in the archive. Doing so might require a great deal more work, though, and might increase the size of the archive.

I just ran a test with zip test code I have at work, and it took around 100 msec to scan the table of contents from the 2012-03 complete.zip and store the information in a std::map. This only needs to be done once at program startup (and again any time the user changes their part library to a different one, of course).
SubjectAuthorViewsPosted
Compressed LDraw files Roland Melkert444January 29, 2013 12:33PM
Re: Compressed LDraw files Tim Gould208January 29, 2013 12:44PM
Re: Compressed LDraw files Travis Cobbs215January 29, 2013 12:49PM
Re: Compressed LDraw files Roland Melkert214January 29, 2013 02:01PM
Re: Compressed LDraw files Tim Gould216January 29, 2013 02:10PM
Re: Compressed LDraw files Ben Supnik245January 29, 2013 10:36PM
Re: Compressed LDraw files Roland Melkert234January 30, 2013 10:52AM
Re: Compressed LDraw files Ben Supnik255January 30, 2013 12:59PM
Re: Compressed LDraw files Allen Smith227January 30, 2013 09:17AM
Compressed Library was Re: Compressed LDraw files Travis Cobbs250January 30, 2013 09:40AM
Re: Compressed Library was Re: Compressed LDraw files Philippe Hurbain231January 30, 2013 09:49AM
Re: Compressed Library was Re: Compressed LDraw files Allen Smith215January 30, 2013 08:43PM
Re: Compressed Library was Re: Compressed LDraw files Travis Cobbs217January 30, 2013 10:27PM
Re: Compressed Library was Re: Compressed LDraw files Roland Melkert253January 31, 2013 09:55AM
Re: Compressed Library was Re: Compressed LDraw files Travis Cobbs240January 31, 2013 11:01AM
Re: Compressed Library was Re: Compressed LDraw files Roland Melkert236January 31, 2013 11:07AM
Re: Compressed Library was Re: Compressed LDraw files Travis Cobbs243January 31, 2013 11:24AM
Re: Compressed Library was Re: Compressed LDraw files Ben Supnik237January 31, 2013 12:26PM
Re: Compressed Library was Re: Compressed LDraw files Roland Melkert243January 31, 2013 01:09PM
Re: Compressed Library was Re: Compressed LDraw files Steffen297February 02, 2013 05:34PM
Re: Compressed Library was Re: Compressed LDraw files Tim Gould264January 31, 2013 04:02PM
Re: Compressed LDraw files Roland Melkert251January 30, 2013 10:57AM
Re: Compressed LDraw files Ben Supnik245January 30, 2013 01:15PM
Re: Compressed LDraw files Roland Melkert240January 30, 2013 02:07PM
Re: Compressed LDraw files Allen Smith205January 30, 2013 08:39PM
Re: Compressed LDraw files Roland Melkert240January 31, 2013 01:06PM
Re: Compressed LDraw files Travis Cobbs246January 31, 2013 01:59PM
Re: Compressed LDraw files Travis Cobbs218January 29, 2013 12:46PM
Re: Compressed LDraw files Roland Melkert210January 29, 2013 01:57PM
Re: Compressed LDraw files Steffen215January 29, 2013 03:23PM
Re: Compressed LDraw files Travis Cobbs248January 29, 2013 04:17PM
Re: Compressed LDraw files Roland Melkert249January 30, 2013 10:49AM
Re: Compressed LDraw files Steffen220February 02, 2013 05:33PM



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